New Formula: omniORB

omniORB is a robust high performance CORBA ORB for C++ and Python.
Python is required by the omniORB IDL compiler.

The omniORBpy Python mapping needs to be installed whithin the omniORB prefix.
omniORBpy is required in order to reach CORBA from Python.

The user needs to amend the PYTHONPATH in order to use both packages.

Formula tested on Snow-Leopard.

fixes on onmiorb formula

added a function to get the prefix of omniORB to be displayed
on the caveats.

Small fixes to comply to current formula style.